Virtual Private Networks (VPNs) are used to interconnect geographically remote offices, campuses, factories, research labs and other facilities of an enterprise across a shared network. The shared network may be a wide-area network (WAN) such as the Internet. The VPN may include an access server, a WAN router and a VPN-dedicated device at each geographic site. VPNs may utilize a Virtual Local Area Network (VLAN), a MultiProtocol Label Switching (MPLS) network or other network.
VLANs group network-connected devices without relation to their physical wiring and constructions. The sending and receiving of frames is performed within the same group and the broadcasting of frames also takes place within the same group. Communication with a different VLAN group generally uses the intermediary of a router.
MPLS provides a virtual communication path in an Internet Protocol (IP) WAN. In particular, MPLS adds a label onto an IP packet that identifies a connection. The network router transmits the IP packet by popping, pushing or swapping the value of the label. In this way, an IP connection-type service is provided.